Speed Jump Rope - Seriously Fast and Adjustable Speed Rope for Double Unders - with Spare Cable, Carry Bag and Ebook - by FitPenguin DESIGNED FOR DOUBLE UNDERS - The FitPenguin Jump Rope is designed specifically for double unders. PRECISION MACHINED - Perfectly balanced aluminum handles, provides accuracy and responsiveness with every jump and keeps you going longer without fatiguing or tripping. FAST & SMOOTH - Advanced ball bearing system and high grade coated steel wire, fast and smooth with no tangling or kinking. ADJUSTABLE - 10 ft (3 m) cable, easily adjusted to the perfect length. 100% GUARANTEED - We want your shopping experience to be worry free, so if you are unhappy for any reason, we will gladly make it right by either replacing your jump rope or refunding your money.